I only have Project Cars but I think it's worth getting just for the visuals, its truly a beautiful game if you have the hardware to support it. Not too expensive either if you shop around I ended up only paying 36 for it.
Just got drive club, tried to Free Version that is now available on the US PSN and it was actually pretty awesome so ended up getting the full game currently $25!!
Anyone playing Driveclub??? Add me, PSN Chooselyfe
I own both, and both are very good. I find myself going back to Driveclub more often. There is just more to do, but the racing is very good on both. Driveclub is a sim/arcade, and Project Cars is more sim. I would say that if you like racing games I would think you would be happy with either.